scholarly journals Two-Stage Channel Adaptive Algorithm for Unmanned Aerial Vehicles Localization with Cellular Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Chenxi Zeng ◽  
Zhongliang Deng ◽  
Jiyang Ma ◽  
Shengsong Yang
Keyword(s):  
Adaptive Algorithm ◽  
High Mobility ◽  
Base Station ◽  
Communication Link ◽  
Observation Error ◽  
Two Stage ◽  
High Coverage ◽  
Lower Altitude ◽  
Channel Environment ◽  
Complex Channel

Unmanned aerial vehicle (UAV) is regarded as a powerful tool to expand the existing ground wireless network into aerial space. Since high mobility is an essential characteristic for UAV, it is important to carry out an accurate, real-time, and high-precision localization in terms of safe operation and communication link maintenance. The cellular network-based localization technology has provided UAV a solution with both high coverage and seamless connection. However, the complex channel environment between the UAV and terrestrial base station (BS) would have weakened the localization performance. To solve this problem, a two-stage channel adaptive algorithm for cellular-connected UAV has been proposed. The first stage of the algorithm is to revise the observation error introduced by the complex channel environment using the model of DDPG. The second stage is to locate the UAV position with TDOA algorithm using the revised observation values. Simulation results have demonstrated that the proposed algorithm can achieve the channel adaptive effect by revising the observation errors and improve location performance greatly, especially for UAVs at a relative lower altitude.

Fast-converging conjugate-gradient adaptive algorithm for complex channel estimation

2010 ◽  
Vol 46 (2) ◽  
pp. 180 ◽  
Author(s):  
Y. Liu ◽  
R. Ranganathan ◽  
M. Hunter ◽  
W. Mikhael
Keyword(s):  
Channel Estimation ◽  
Conjugate Gradient ◽  
Adaptive Algorithm ◽  
Complex Channel

An Accurate, Robust and Low Dimensionality Deep Learning Localization Approach in DM-MIMO Systems Based on RSS

2021 ◽  
Author(s):  
Seyedeh Samira Moosavi ◽  
Paul Fortier
Keyword(s):  
Massive Mimo ◽  
Clustering Algorithm ◽  
Mean Squared Error ◽  
Mimo Systems ◽  
Principal Component ◽  
Base Station ◽  
Location Estimation ◽  
Similar Data ◽  
High Coverage ◽  
Single Antenna

Abstract Currently, localization in distributed massive MIMO (DM-MIMO) systems based on the fingerprinting (FP) approach has attracted great interest. However, this method suffers from severe multipath and signal degradation such that its accuracy is deteriorated in complex propagation environments, which results in variable received signal strength (RSS). Therefore, providing robust and accurate localization is the goal of this work. In this paper, we propose an FP-based approach to improve the accuracy of localization by reducing the noise and the dimensions of the RSS data. In the proposed approach, the fingerprints rely solely on the RSS from the single-antenna MT collected at each of the receive antenna elements of the massive MIMO base station. After creating a radio map, principal component analysis (PCA) is performed to reduce the noise and redundancy. PCA reduces the data dimension which leads to the selection of the appropriate antennas and reduces complexity. A clustering algorithm based on K-means and affinity propagation clustering (APC) is employed to divide the whole area into several regions which improves positioning precision and reduces complexity and latency. Finally, in order to have high precise localization estimation, all similar data in each cluster are modeled using a well-designed deep neural network (DNN) regression. Simulation results show that the proposed scheme improves positioning accuracy significantly. This approach has high coverage and improves average root-mean-squared error (RMSE) performance to a few meters, which is expected in 5G and beyond networks. Consequently, it also proves the superiority of the proposed method over the previous location estimation schemes.

Texture and Ductility of Ni3Al Foils

2011 ◽  
Vol 306-307 ◽  
pp. 116-119
Author(s):  
Masahiko Demura ◽  
Ya Xu ◽  
Toshiyuki Hirano
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Memory Effect ◽  
Texture Evolution ◽  
High Mobility ◽  
Two Stage ◽  
Texture Memory ◽  
Highly Effective ◽  
Cold Rolled

This article presents the texture evolution and the ductility improvement of the cold-rolled foils of boron-free Ni3Al during the recrystallization and the subsequent grain growth. The cold-rolled foils had sharp {110} textures. After the recrystallization at 873K/0.5h, the texture was disintegrated with several texture components. Interestingly, most of them had a single rotation relationship. i.e. 40˚ around <111>. With the progress of the grain growth, however, the texture returned to the sharp, cold-rolled textures. This two-stage texture evolution, called as “Texture memory effect”, was explained assuming a high mobility of the grain boundary with the 40˚<111> rotation relationship. The texture returning was highly effective to improve the ductility of the foils.

scholarly journals Computed tomography images de-noising using a novel two stage adaptive algorithm

2015 ◽  
Vol 5 (4) ◽  
pp. 220
Author(s):  
Hamidreza Saberkari ◽  
Mojtaba Fadaee ◽  
Mousa Shamsi ◽  
MohammadHossein Sedaaghi
Keyword(s):  
Computed Tomography ◽  
Adaptive Algorithm ◽  
Two Stage ◽  
Computed Tomography Images

An Asynchronous Multi-Channel MAC Protocol Based on Cooperation Mechanism in Vehicular AdHoc Network

2015 ◽  
Vol 713-715 ◽  
pp. 1294-1298
Author(s):  
Xin Yun Li ◽  
Lun Tang
Keyword(s):  
Network Reliability ◽  
Mac Protocol ◽  
High Mobility ◽  
Collision Probability ◽  
Delivery Ratio ◽  
Adhoc Network ◽  
Cooperation Mechanism ◽  
Hidden Terminals ◽  
Hidden Terminal ◽  
Channel Environment

To solve the problem of vehicle adhoc network reliability is not high and multi-channel hidden terminals, we propose a multi-channel MAC protocol CAMP(cooperation-based asynchronous multi-channel MAC protocol) based mechanism for asynchronous cooperation in VANET. CAMP add to cooperation mechanisms in asynchronous multi-channel environment, the proposed scheme nodes cooperation in order to obtain the channel state information and status information to other nodes, thus a good solution to the hidden terminal problem multichannel transmission process, to achieve high mobility environment under the reliable transmission of data. The simulation results show that CAMP has better performance than IEEE 1609.4 standard, AMCP protocol, AMCMAC protocol on collision probability of SCH, safety messages delivery ratio.

Millimeter-Wave Base Station Cooperation Technologies for High-Mobility Environments

2021 ◽  
Author(s):  
Tatsuki Okuyama ◽  
Satoshi Suyama ◽  
Nobuhide Nonaka ◽  
Takahiro Asai
Keyword(s):  
Millimeter Wave ◽  
High Mobility ◽  
Base Station ◽  
Base Station Cooperation

scholarly journals Analysis and Design of SCMA-Based Hybrid Unicast-Multicast Relay-Assisted Networks

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 329 ◽  
Author(s):  
Yibo Zhang ◽  
Xiaoxiang Wang ◽  
Dongyu Wang ◽  
Yufang Zhang ◽  
Yanwen Lan
Keyword(s):  
Outage Probability ◽  
Cooperative Diversity ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Cooperative Transmission ◽  
High Signal ◽  
Transmission Scheme ◽  
Two Stage ◽  
Analysis And Design ◽  
Relay Location

This paper studies a multi-user network model based on sparse code multiple access (SCMA), where both unicast and multicast services are considered. In the direct transmission scheme, the communication between the base station (BS) and the users is completed with one stage, in which the relay is inexistent. In the two-stage cooperative transmission scheme, any number of relays are placed to improve the reliability of wireless communication system. The BS broadcasts the requested message to users and relays in the first stage, and the successful relays forward the message to unsuccessful users in the second stage. To characterize the performance of these two schemes, we derive the exact and approximate expressions of average outage probability. Furthermore, to take full advantage of the cooperative diversity, an optimal power allocation and relay location strategy in the high signal-to-noise ratio (SNR) regime is studied. The outage probability reaches the minimum value when the first stage occupies half of the total energy consumed. Simulation and analysis results are presented to demonstrate the performance of these two schemes. The results show that the two-stage cooperative scheme effectively reduce the average outage probability in SCMA network, especially in the high SNR region.

scholarly journals High Throughput Data Relay in UAV Wireless Networks

2020 ◽  
Vol 12 (11) ◽  
pp. 193
Author(s):  
Fenyu Jiang ◽  
Chris Phillips
Keyword(s):  
Wireless Networks ◽  
Bandwidth Allocation ◽  
High Mobility ◽  
Base Station ◽  
Bandwidth Scheduling ◽  
Promising Tool ◽  
Fair Bandwidth Allocation ◽  
Balance Mechanism ◽  
General Method

As a result of their high mobility and reduced cost, Unmanned Aerial Vehicles (UAVs) have been found to be a promising tool in wireless networks. A UAV can perform the role of a base station as well as a mobile relay, connecting distant ground terminals. In this paper, we dispatch a UAV to a disaster area to help relay information for victims. We involve a bandwidth efficient technique called the Dual-Sampling (DS) method when planning the UAV flight trajectory, trying to maximize the data transmission throughput. We propose an iterative algorithm for solving this problem. The victim bandwidth scheduling and the UAV trajectory are alternately optimized in each iteration, meanwhile a power balance mechanism is implemented in the algorithm to ensure the proper functioning of the DS method. We compare the results of the DS-enabled scheme with two non-DS schemes, namely a fair bandwidth allocation scheme and a bandwidth contention scheme. The DS scheme outperforms the other two non-DS schemes regarding max-min average data rate among all the ground victims. Furthermore, we derive the theoretical optimal performance of the DS scheme for a given scenario, and find that the proposed approach can be regarded as a general method to solve this optimization problem. We also observe that the optimal UAV trajectory for the DS scheme is quite different from that of the non-DS bandwidth contention scheme.

Sign in / Sign up

Export Citation Format

Share Document